v2.4.1.9

Supplemental Guarantor Information Condensed Consolidated Statements of Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Guarantor Information [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 234.6us-gaap_ComprehensiveIncomeNetOfTax	$ 126.1us-gaap_ComprehensiveIncomeNetOfTax	$ 121.5us-gaap_ComprehensiveIncomeNetOfTax
Parent Guarantor [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	234.6us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	126.1us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	121.5us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Subsidiary Issuer [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	234.6us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiaryIssuerMember	141.3us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiaryIssuerMember	121.5us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiaryIssuerMember
Guarantor Subsidiaries [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	484.6us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_GuarantorSubsidiariesMember	409.0us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_GuarantorSubsidiariesMember	322.8us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_GuarantorSubsidiariesMember
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	5.1us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_NonGuarantorSubsidiariesMember	4.8us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_NonGuarantorSubsidiariesMember	13.2us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_NonGuarantorSubsidiariesMember
Co-Issuer [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	0us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cdw_CoIssuerMember	0us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cdw_CoIssuerMember	0us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cdw_CoIssuerMember
Consolidating Adjustments [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(724.3)us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidationEliminationsMember	(555.1)us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidationEliminationsMember	(457.5)us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidationEliminationsMember
Consolidated [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 234.6us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidatedEntitiesMember	$ 126.1us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidatedEntitiesMember	$ 121.5us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidatedEntitiesMember

X

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=6519514



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=35737396



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e557-108580



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Net Income

-URI http://asc.fasb.org/extlink&oid=6518256

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